Delay in sidefill....

[cubiejeff]

Can anyone tell me, why is there a delay of sound when I patches the following in this way.

 

All the bands equipment to a mixer-> send a line out to the main mixer. This main mixer received all mics, cd player..... When this main mixer send signal to amp rack below FOH.. its normal. But when it reaches the amp rack for reinforcement speakers at the back of the venue (reinforcement speakers and amp rack is about 100m away from the main mixer, my reinforcement amp rack equips with an EQ..).. GONE.. Its delay for about a second or 2.

 

Is my wire to long from the main to the reinforcement? Does it concern with the EQ in the amprack? Is there any other device to push it... Or it is normal? Please advice.. thanks in advance..

[Pete]

More information please!

 

Is this a digital mixer?Digital EQ?

 

Have you measured the delay to a SECOND?Because thats an awfully long time!

[boogiebehometh]

yeah - guess we'd need more info, esp on testing methods n if u're using digital eqptmt

 

even digital stuffs that lag beyond 20ms r considered very bad....

this sounds stupid, but,

if u're using your ears n standing at the mixers with reinforcement speakers 100m away n u're testing with your ears,

u ought subtract 100/330=0.3secs from your results cos sound takes time to travel >_<

)

 

ehms, I was joking, ** laughs out loud **, but u see the analogy :)

 

 

<_< PLEASE DON'T USE TXT SPEAK! It can cause confusion, and is unwelcome on this forum.

[Pete McCrea]

If it's an installed system and the reinforcement speakers at the back are cabled from a permanently installed equipment rack, there is a 95% chance that there will be a delay unit in that rack/signal path to make sure that the sound waves coming from the reinforcement speakers leave the cabinet as the wave front from the main FOH PA arrives at the reinforcement cabinets.

 

But that is speculation based on the assumption of it being a properly installed system with correctly set up delays.

[BlueShift]

But that is speculation based on the assumption of it being a properly installed system with correctly set up delays.

 

A brave speculation indeed! <_<

[cubiejeff]

haha... such a good analogy..

 

I patches all wireless mics to Mackie analog 32 channel mixer with alexis reverb and yamaha 31 band EQ to my active long throw speakers for FOH.. I spilted the signal from the EQ to the reinforcement amp rack then to the passive full range speaker at the back of the venue.. It has a slight delay, its the delay for speeches.. Not delay from the reverb.. Is my cabling too long. By the way. its not a permanent installation, its mobile system.

[Simon Lyall]

I severely doubt your cable is too long, as the signal along your cable (assuming your sending it as an electrical signal) will be close to the speed of light, its going to be something else, what else I haven't got a clue!

 

Simon

[Brian]

How do you know there is a delay?

[cubiejeff]

I send normal sound signal cable out from main control's EQ to the amp rack for reinforcement speakers. Is there any way to solve it?

[boogiebehometh]

haha... such a good analogy..

 

I patches all wireless mics to Mackie analog 32 channel mixer with alexis reverb and yamaha 31 band EQ to my active long throw speakers for FOH.. I spilted the signal from the EQ to the reinforcement amp rack then to the passive full range speaker at the back of the venue.. It has a slight delay, its the delay for speeches.. Not delay from the reverb.. Is my cabling too long. By the way. its not a permanent installation, its mobile system.

I'm pretty much lost, ** laughs out loud **.... <_<

but if what we've learnt recently at school is correct, one thing that can be ruled out might be the length of the cables for 100m - reason being the electrons at the mixing desk might never reach the amp rack at the back of the venue for the signal to be delivered :)

[Brian]

I send normal sound signal cable out from main control's EQ to the amp rack for reinforcement speakers. Is there any way to solve it?

Sorry, my point was how are you measuring/hearing the delay? Is it as simple as you being nearer the main PA than the sidefills. Remember, sound travels at around 300m per second so if you are 100m nearer the main than the fill then you'll hear a 1/3rd second delay.

[cubiejeff]

we have projector screens at the back where people can have a closed up look of the stage.. We noticed that the lips of the person singing doesn't match with the sound. We are hearing from the reinforcement speaker. Sound is slower.

[MarkPAman]

The light from the image you are seeing travels so fast that over 100m we can say it gets there instantly.

However the sound is much slower:

 

Remember, sound travels at around 300m per second so if you are 100m nearer the main than the fill then you'll hear a 1/3rd second delay.

 

If this is what you are hearing then nothing is wrong, this is what you would expect. :(

If you are getting 1 to two seconds delay, then there is still a problem to solve. :D

 

OT (a bit). Is it common to delay a video signal to a screen, so that a larger proportion of the audience see/hear things at the same time?

[Seano]

OT (a bit). Is it common to delay a video signal to a screen, so that a larger proportion of the audience see/hear things at the same time?

 

Don't know about video, but its pretty standard practice with cinema film projection. (And being film the delay is easy to arrange, its just a question of a bit more or less film between the gate and the sound head.)

 

Sean

x

[Mark Payne]

Oh yes, 100% normal proceedure.

 

Actually in smaller venues it can work the other way around. Once you have a couple of vision mixers and switchers/scalers and the screens own processor (LED), the frame delay of this little lot makes the image lag the sound for the majority of the audience.

 

You end up having to time align the PA to the screen.

 

However... take a big venue with people say over 50M from the stage and you have 150ms of sound propogation delay to deal with. You will have to delay the screen for them... but then it will be over-delayed for the people at the front.... its a compromise.

 

Cheers

 

Mark

 

If this is what you are hearing then nothing is wrong, this is what you would expect. :)

If you are getting 1 to two seconds delay, then there is still a problem to solve. :)

 

OT (a bit). Is it common to delay a video signal to a screen, so that a larger proportion of the audience see/hear things at the same time?